IAP logo UniBonn logo
  • Increase font size
  • Default font size
  • Decrease font size

Quantum technologies

Dieter Meschede's research group
Home AMO physics colloquia
  • Prof. Matthias Weidemüller

  • Invited speaker: Prof. Matthias Weidemüller
    Affiliation: Ruprecht-Karls-Universität Heidelberg
    Title: Rydberg Aggregates
    Time and room: 17 h c.t., lecture hall IAP
    Abstract: Due to the long-range character of the interaction between highly excited atoms, the dynamics of an ultracold gas of Rydberg atoms is entirely determined by van-der-Waals and dipole-dipole interactions. One outstanding property is the tunability of the strength and the character of the interactions with static electric fields. This allows one to explore the transition from a weakly coupled two-body system to a strongly coupled many-body system. The long-range interaction leads to many-body entanglement and has possible applications in quantum computing. In my talk I will first give a general introduction into the field of Rydberg gases with special emphasis on our recent experiments.

  • Prof. Hanns-Christoph Nägerl

  • Invited speaker: Prof. Hanns-Christoph Nägerl
    Affiliation: Universität Innsbruck
    Title: Strongly correlated one-dimensional quantum systems
    Time and room: 17 h c.t., lecture hall IAP
    Abstract: I will review our recent experiments with atomic quantum gases in the regime of quantum degeneracy, Bose-Einstein condensation, and strong correlations. Ultracold atomic gases are versatile tunable laboratory systems for the study of complex many-body quantum phenomena as essentially all parameters such as geometry and strength of confinement and the strength of interactions [1] can be controlled with near-perfect isolation from external perturbations. For atoms 1D geometry, I will discuss the strongly-interacting limits of so-called Tonks-Girardeau and super-Tonks-Girardeau phases [2]. We observe the “pinning” quantum phase transition in the presence of an arbitrarily weak lattice potential [3]. Exploiting three-body recombination processes, we determine the value of the three-particle correlation function at the origin from weak to strong interactions [4]. I will finally discuss measurements of impurity transport through a strongly interacting 1D system.

    [1] E. Haller et al., Phys. Rev. Lett. 104, 153203 (2010); [2] E. Haller et al., Science 325, 1224 (2009); [3] E. Haller et al., Nature 466, 597 (2010); [4] E. Haller et al., manuscript in preparation.

  • Prof. Andreas Ruschhaupt

  • Invited speaker: Prof. Andreas Ruschhaupt
    Affiliation: Leibniz Universität Hannover
    Title: Shortcuts to Adiabaticity
    Time and room: 17 h c.t., lecture hall IAP
    Abstract: We present new methods to achieve shortcuts to adiabatic manipulations of atoms in a harmonic trap: a speeded-up adiabatic-like expansion of the trap and a speeded-up adiabatic-like transport of the trap. In both cases, the final atomic state is the same as in the adiabatic process, but the state is achieved with fidelity one in arbitrarily short time, keeping the same populations of vibrational levels in the initial and final trap. These methods can also be generalized to condensates. Moreover, we show how to speed up adiabatic passage from one internal atomic state to another in two-level and three-level atoms.

  • Dr. Ulrich Vogl

  • Invited speaker: Dr. Ulrich Vogl
    Affiliation: NIST Gaithersburg and Joint Quantum Institute
    Title: Quantum Image Processing with Four-Wave Mixing in Hot Atomic Vapor
    Time and room: 17 h c.t., IAP lecture room
    Abstract: Four-wave-mixing in hot atomic vapor is a versatile tool for spatially multimode squeezed light generation. We demonstrate multimode behaviour for different pump-probe configurations producing either single mode squeezing or twin beams. To illustrate the interest of such fields, we perform an imaging experiment with two quantum correlated vacuum beams, where the spatially multimode character of squeezing is used to reconstruct an arbitrarily chosen pattern. We investigate the advantage of squeezing in this configuration and we demonstrate an enhanced sensitivity due to quantum correlations. 

  • Prof. Achim Peters

  • Invited speaker: Prof. Achim Peters
    Affiliation: Humboldt-Universität zu Berlin
    Title: Atom Interferometry - from thought experiment to applications on Earth and in space
    Time and room: 11 h c.t., HISKP lecture room.
    Abstract: Since the demonstration of the first atom interferometers in 1991, this technique has evolved from an interesting demonstration of quantum mechanics into a new measurement tool that rivals, if not surpasses, the capabilities of classical instruments.

    This talk will review the principles underlying atom interferometry and discuss the perspectives of inertial quantum sensors based on laser cooled atoms and atomic quantum gases. One such instrument that is currently under development at the Humboldt-University for applications in geophysics and geodesy is the mobile Quantum Gravimeter GAIN, with a target accuracy of a few parts in 10^10 for measurements of local gravity.

    Another project which ultimately aims at performing high precision atom interferometry is QUANTUS. After the first demonstration of Bose-Einstein-Condensation in microgravity at the ZARM droptower in 2007 and more than 200 successful drop experiments since then, the QUANTUS collaboration is now aiming at performing precision quantum test of the equivalence principle in Earth orbit by ~ 2018. As an important next step, an improved version of the drop tower experiment is to be launched into space on a ballistic sounding rocket as early as 2013.

    The space experiments in particular, but also those instruments targeting practical applications on the ground, depend to a large degree on the availability of robust and compact laser system technology. The implementation of the new Laser Metrology Group at the FBH addresses this need by developing a new generation of miniaturized, hybrid integrated laser diode systems specifically optimized for precision applications. I will present a number of examples and discuss future perspectives and challenges.

Open projects